The most common way to physically exclude people from an enclosed area or space is by use of a lock. A lock can be incorporated into a door or other structure, or it can be a separate device (e.g. a padlock) that secures a door or structure to an adjoining wall or structure. It is common for a given person or organization to have a number of locks and associated keys. It is also common for a person to forget which key corresponds to which lock, as well as to forget what a given key is for. For example, a person can have a key ring or key chain with several keys on it. Several of the keys can have a similar configuration. If the keys are not marked then the user may not be able to distinguish them. This problem can be greatly compounded when a person who routinely uses the keys is unavailable, and a person unfamiliar with the keys must find one or more keys to unlock or lock a given lock or locks. In another example, it is not uncommon for a person who has a key ring to, over time, collect keys to various lock, and through a lack of use, forget which lock one or more of the keys is for.
This problem has been addressed by using identifiers on one or more keys. For example, a commonly available product is a key identifier that is a part that goes over the handle of a key. Typically these are sold in packages with several key identifiers that are all different colors. Each color can be used to identify a different lock/door to which the particular key on which the key identifier is placed corresponds. However this system relies on the person's memory, and a different person may not know the color scheme, or the person may forget which color corresponds to which door/lock. In addition, if there are a large number of keys, a color scheme of several color may not be enough, and if other visual characteristics are used, it can be impractical for a person to memorize all of the key identifiers. In the case of a large number of keys, it is also common to simply include indicia on each key, such as, for example, a room number, to identify the lock to which the key corresponds. However that may be undesirable in some circumstances where it may be desirable to keep the identification of a lock/key pair such that unauthorized parties cannot identify the lock given the key.
Therefore, a need exists to overcome the problems with the prior art as discussed above.